Method and Detection System for Detecting Internal Defects of Light-Absorbing Glass

Abstract

The present invention relates to a method and a detection system for detecting internal defects of a light-absorbing glass. The detection method includes: 1) heating a light-absorbing glass specimen; calculating the theoretical thermal conductivity of the light-absorbing glass according to the glass composition; 2) detecting the temperature distribution on the surface of the specimen; determining the temperature mutation region and its volume size according to the temperature distribution; 3) continuously measuring the real-time temperature values of the specimen at different rod lengths; calculating the actual thermal conductivity of the light-absorbing glass according to the thermal radiation energy, the thickness and the cross-sectional area of the specimen; 4) determining the type of internal defects according to the temperature distribution on the surface of the specimen; determining the material type of the internal defects according to the volume size of the temperature mutation region, the theoretical thermal conductivity and the actual thermal conductivity of the light-absorbing glass. The technical problem to be solved is to change the detection of internal defects of the light-absorbing glass from post-destructive inspection to pre-inspection, so as to timely obtain product quality information, which can not only improve the inspection efficiency but also save costs.

Description

Technical Field

[0001] The present invention belongs to the technical field of glass detection, and particularly relates to a method and a system for detecting internal defects of light-absorbing glass. Background Art

[0002] The fiber optic image transmission element is an optical device prepared from a variety of glass materials, which mainly includes the cortical glass, core glass of the optical fiber, and light-absorbing glass. The light-absorbing glass in the fiber optic image transmission element can play a role in absorbing stray light between the optical fibers, thereby improving the contrast and resolution of the fiber optic image transmission element.

[0003] The composition design of the light-absorbing glass is based on the system of the cortical glass of the optical fiber, and then coloring metal ions are introduced into it. For example, commonly used ones include iron ions, cobalt ions, nickel ions, manganese ions, copper ions, etc. In order to achieve a good visible light absorption effect, a multi-ion composite coloring method is often used, so that different ions can absorb light of specific wavelengths, and the glass body can also perform intrinsic light absorption on X-rays and ultraviolet light. Therefore, the light-absorbing glass in the fiber optic image transmission element may have a very broad spectral absorption range. When the concentration of the composite coloring ions introduced into the glass is higher, the glass may become a wide-spectrum blackbody glass due to devitrification, and even the transmittance in the near, middle, and far infrared bands is significantly reduced.

[0004] The transparent core glass and cortical glass can detect internal defects through conventional optical and electronic detection means, so as to avoid using glass materials with unqualified internal quality in the fiber optic image transmission element. However, due to the broad spectral absorption range of the light-absorbing glass, no matter which of the multiple optical detection methods based on X-rays, ultraviolet rays, visible light, or even infrared rays are used, they are not applicable to the performance detection of the opaque light-absorbing glass in the fiber optic image transmission element, and it is also impossible to screen out light-absorbing glass with unqualified internal quality through traditional detection means. As a result, it may lead to defects in the fiber optic image transmission element due to the internal quality defects of the light-absorbing glass, especially the proportion of air bubbles and dark spots is particularly high, resulting in a low product qualification rate. On the other hand, due to the lack of effective internal quality detection means for the opaque light-absorbing glass, it is impossible to provide performance data for the design and melting process optimization of the light-absorbing glass composition, and only after-final inspection or destructive inspection can be used to obtain corresponding data for formula and process optimization, which is both costly and inefficient. Summary of the Invention

[0005] The main purpose of the present invention is to provide a method and a system for detecting internal defects of light-absorbing glass. The technical problem to be solved is to change the detection of internal defects of light-absorbing glass from post-destructive inspection to pre-inspection, so as to timely obtain product quality information, which can not only improve the inspection efficiency but also save costs, and thus be more suitable for practical use.

[0006] The object of the present invention and the technical problems to be solved are achieved by the following technical solutions. A method for detecting internal defects in a light-absorbing glass according to the present invention includes the following steps:

[0007] 1) Heating a rod-shaped light-absorbing glass specimen; calculating the theoretical thermal conductivity of the light-absorbing glass according to the composition of the light-absorbing glass;

[0008] 2) Detecting the temperature distribution on the surface of the light-absorbing glass specimen; determining the temperature mutation region and the volume size of the temperature mutation region according to the temperature distribution on the surface of the specimen;

[0009] 3) Continuously measuring the real-time temperature values of the light-absorbing glass specimen at different rod length positions; calculating the actual thermal conductivity of the light-absorbing glass according to the thermal radiation energy, the thickness and cross-sectional area of the light-absorbing glass rod specimen;

[0010] 4) Determining the type of internal defect according to the temperature distribution on the surface of the light-absorbing glass specimen; determining the material type of the internal defect according to the volume size of the temperature mutation region, the theoretical thermal conductivity of the light-absorbing glass and the actual thermal conductivity of the light-absorbing glass.

[0011] The object of the present invention and the technical problems to be solved can also be further achieved by the following technical measures.

[0012] Preferably, in the foregoing method for detecting internal defects in a light-absorbing glass, the light-absorbing glass specimen is in a round rod shape; the surface of the round rod-shaped specimen is flat, and its diameter deviation ≤ 0.1 mm; or, the light-absorbing glass specimen is in a square rod shape; the four side surfaces of the square rod-shaped specimen are precision-ground surfaces and are perpendicular to each other, and the included angle between two adjacent side surfaces is 89.5° - 90.5°.

[0013] Preferably, in the foregoing method for detecting internal defects in a light-absorbing glass, the volume size of the temperature mutation region is determined according to the following steps:

[0014] Performing radiant heating along the axis direction of the light-absorbing glass specimen, and measuring the longest length of the internal defect along the rod length direction as L z , and the cross-sectional area is S z ;

[0015] Performing radiant heating along the cross-sectional direction of the light-absorbing glass specimen, and measuring the longest length of the internal defect along the cross-sectional direction as L j , and the cross-sectional area is S j ;

[0016] According to the formula V = (S j ×L z +S z ×L j) / 2 to calculate the volume size of the temperature mutation region.

[0017] Preferably, in the above-described method for detecting internal defects of light-absorbing glass, the step of determining the type of internal defects according to the temperature distribution on the surface of the light-absorbing glass specimen specifically includes the following steps:

[0018] Perform radiant heating along the axis direction of the light-absorbing glass specimen, and obtain the detection result in this direction through an infrared thermal imager;

[0019] Perform radiant heating along the cross-section direction of the light-absorbing glass specimen, and obtain the detection result in this direction through an infrared thermal imager;

[0020] Taking the position in the bar length direction of the light-absorbing glass specimen as the abscissa and the temperature at each position of the light-absorbing glass specimen as the ordinate, draw a temperature distribution curve; the internal defect existing at the position where the peak shape is located on the temperature distribution curve is a nodule defect, and the internal defect existing at the position where the valley shape is located is a bubble defect.

[0021] Preferably, in the above-described method for detecting internal defects of light-absorbing glass, when performing radiant heating along the axis direction of the light-absorbing glass specimen, the full width at half maximum of the peak shape or valley shape of the temperature distribution curve is equal to the longest length L of the internal defect along the bar length direction z ; when performing radiant heating along the cross-section direction of the light-absorbing glass specimen, the full width at half maximum of the peak shape or valley shape of the temperature distribution curve is equal to the longest length L of the internal defect along the cross-section direction j ; the full width at half maximum is calculated according to the following steps:

[0022] Take the highest value and the lowest value of the measured temperature of the peak shape or valley shape, and calculate the average value of the two; taking this average value as the ordinate, draw a straight line parallel to the X-axis, and the distance between the two intersection points of this straight line and the temperature distribution curve is the full width at half maximum.

[0023] Preferably, in the above-described method for detecting internal defects of light-absorbing glass, the step of determining the material type of the internal defect according to the volume size of the temperature mutation region, the theoretical thermal conductivity of the light-absorbing glass, and the actual thermal conductivity of the light-absorbing glass specifically includes the following steps:

[0024] a. Obtain the thermal conductivity and density data of the possible materials of the internal defect from the database;

[0025] b. Substitute the thermal conductivity and density data of the possible materials of the internal defect into the following formula to check whether the following equation holds;

[0026]

[0027] Wherein, λ0 represents the thermal conductivity of the internal defect, λ1 represents the theoretical thermal conductivity of the light-absorbing glass, λ2 represents the actual thermal conductivity of the light-absorbing glass, V represents the volume of the internal defect (unit: mm 3 ) and ρ0 represents the density of the internal defect (unit: g / mm 3 ).

[0028] c. If the equation does not hold, replace it with another possible material of the internal defect and continue to execute steps a and b; if the equation holds, the possible material of this kind of internal defect is determined as the material type of the internal defect.

[0029] The object of the present invention and the technical problems solved by it are also achieved by the following technical solutions. A light-absorbing glass internal defect detection system proposed according to the present invention includes:

[0030] A heating unit for heating the light-absorbing glass specimen;

[0031] A test platform for placing the heating unit and the light-absorbing glass specimen; a bracket and a three-dimensional precision mechanical transmission device are arranged on the test platform; the bracket is used for clamping the light-absorbing glass specimen; the three-dimensional precision mechanical transmission device is used for adjusting the position of the light-absorbing glass specimen in a three-dimensional space;

[0032] A detection unit for detecting the temperature distribution on the surface of the light-absorbing glass specimen;

[0033] A frame for fixing the detection unit;

[0034] A dark box including a heat insulation layer; the test platform and the detection unit are both arranged in the dark box;

[0035] A control unit is electrically connected to the heating unit, the detection unit and the three-dimensional precision mechanical transmission device, controls the three-dimensional precision mechanical transmission device to move the light-absorbing glass specimen according to instructions, the heating unit heats the light-absorbing glass specimen, and controls the detection unit to monitor the temperature distribution on the surface of the light-absorbing glass specimen in real time; the detection unit transmits the acquired data information to the control unit for result determination.

[0036] The object of the present invention and the technical problems solved by it can also be further realized by the following technical measures.

[0037] Preferably, in the aforementioned light-absorbing glass internal defect detection system, the positioning accuracy of the three-dimensional precision mechanical transmission device is ≤3.0 μm, and the repeat positioning accuracy is ≤2.0 μm.

[0038] Preferably, in the above-described internal defect detection system for light absorption glass, the heating unit is a metal conductive hot plate or an infrared heating panel; when using a metal conductive hot plate for heating, the detection unit is two thermal imagers; when using an infrared heating panel for heating, the detection unit is two thermal imagers and an infrared spectrophotometer.

[0039] Preferably, in the above-described internal defect detection system for light absorption glass, a number of independent spaces that do not leak light from each other are provided in the dark box; each of the thermal imagers is placed in a different independent space.

[0040] Preferably, in the above-described internal defect detection system for light absorption glass, the sensitivity of the thermal imager is higher than 0.025 °C, the temperature measurement accuracy is ±0.5 °C, and the temperature measurement range is 0 to 200 °C.

[0041] Preferably, in the above-described internal defect detection system for light absorption glass, the test wavelengths of the spectrophotometer are 290 nm to 2500 nm and 2500 nm to 10000 nm, the transmittance accuracy is ±0.2%, and the resolution is 5 nm.

[0042] By means of the above technical solutions, the internal defect detection method and detection system for light absorption glass proposed by the present invention at least have the following advantages:

[0043] The internal defect detection method and detection system for light absorption glass proposed by the present invention can change the detection of internal defects of light absorption glass from post-destructive inspection to pre-inspection, realizing non-destructive detection of internal defects of opaque light absorption glass; through the detection results of the internal defects, quality evaluation data can be provided for the design of the composition of light absorption glass and the optimization of the melting process, thereby avoiding the situation in the research and development process where only the post-detection results of the final product can be used to judge whether the composition design of light absorption glass is reasonable and whether the melting process is reasonable. Further, the technical solution of the present invention can monitor the quality of products made of light absorption glass in advance, prevent unqualified light absorption glass from entering the production process, not only effectively improve the yield of the final product, but also improve the inspection efficiency and save costs.

[0044] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly and implement it in accordance with the content of the specification, the following will be described in detail with reference to the preferred embodiments of the present invention and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is the absorption curve of the light absorption glass applicable to the detection method of the present invention;

[0046] Figure 2Schematic diagram of the internal defect detection system for absorbing glass - metal conductive hot plate type;

[0047] Figure 3 Schematic diagram of the internal defect detection system for absorbing glass - infrared heating panel type;

[0048] Figure 4a Temperature distribution map on the surface of the light - absorbing glass specimen - infrared heating panel for thermal conductivity defect;

[0049] Figure 4b Temperature distribution map on the surface of the light - absorbing glass specimen - metal conductive heating body for thermal conductivity defect;

[0050] Figure 4c Temperature distribution map on the surface of the light - absorbing glass specimen - infrared heating panel for heat insulation defect;

[0051] Figure 4d Temperature distribution map on the surface of the light - absorbing glass specimen - metal conductive heating body for heat insulation defect;

[0052] Figure 5 Schematic diagram of applying heat radiation along the length direction of the glass rod in Example 1;

[0053] Figure 6a Test result of the internal defect length output by the thermal imager when applying heat radiation along the length direction of the glass rod in Example 1;

[0054] Figure 6b Test result of the internal defect cross - sectional area output by the thermal imager when applying heat radiation along the length direction of the glass rod in Example 1;

[0055] Figure 6c Temperature distribution curve of the measured light - absorbing glass specimen along the length direction of the glass rod in Example 1;

[0056] Figure 7 Schematic diagram of applying heat radiation in the cross - section direction of the glass in Example 1;

[0057] Figure 8a Test result of the internal defect length output by the thermal imager when applying heat radiation in the cross - section direction of the glass in Example 1;

[0058] Figure 8b Test result of the internal defect cross - sectional area output by the thermal imager when applying heat radiation in the cross - section direction of the glass in Example 1;

[0059] Figure 8c Temperature distribution curve of the measured light - absorbing glass specimen in the cross - section direction of the glass in Example 1;

[0060] Figure 9 Schematic diagram of applying heat radiation along the length direction of the glass rod in Example 2;

[0061] Figure 10a It is the test result of the internal defect length output by the thermal imager when applying heat radiation along the length direction of the glass rod in Example 2;

[0062] Figure 10b It is the test result of the internal defect cross-sectional area output by the thermal imager when applying heat radiation along the length direction of the glass rod in Example 2;

[0063] Figure 10c It is the temperature distribution curve of the measured light-absorbing glass specimen along the length direction of the glass rod in Example 2;

[0064] Figure 11 It is a schematic diagram of applying heat radiation in the cross-sectional direction of the glass in Example 2;

[0065] Figure 12a It is the test result of the internal defect length output by the thermal imager when applying heat radiation in the cross-sectional direction of the glass in Example 2;

[0066] Figure 12b It is the test result of the internal defect cross-sectional area output by the thermal imager when applying heat radiation in the cross-sectional direction of the glass in Example 2;

[0067] Figure 12c It is the temperature distribution curve of the measured light-absorbing glass specimen in the cross-sectional direction of the glass in Example 2;

[0068] Figure 13 It is a schematic diagram of applying heat radiation along the length direction of the glass rod in Example 3;

[0069] Figure 14a It is the test result of the internal defect length output by the thermal imager when applying heat radiation along the length direction of the glass rod in Example 3;

[0070] Figure 14b It is the test result of the internal defect cross-sectional area output by the thermal imager when applying heat radiation along the length direction of the glass rod in Example 3;

[0071] Figure 14c It is the temperature distribution curve of the measured light-absorbing glass specimen along the length direction of the glass rod in Example 3;

[0072] Figure 15 It is a schematic diagram of applying heat radiation in the cross-sectional direction of the glass in Example 3;

[0073] Figure 16a It is the test result of the internal defect length output by the thermal imager when applying heat radiation in the cross-sectional direction of the glass in Example 3;

[0074] Figure 16bIt is the test result of the cross-sectional area of internal defects output by the thermal imager when applying thermal radiation in the cross-sectional direction of the glass in Example 3;

[0075] Figure 16c It is the temperature distribution curve of the measured light-absorbing glass specimen in the cross-sectional direction of the glass in Example 3. Detailed implementation manners

[0076] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following combines the drawings and preferred embodiments to detail the specific implementation manners, structures, features, and effects of a method and a detection system for detecting internal defects of light-absorbing glass proposed according to the present invention as follows.

[0077] The present invention proposes a method for detecting internal defects of light-absorbing glass, which includes the following steps:

[0078] 1) Heating a rod-shaped light-absorbing glass specimen; calculating the theoretical thermal conductivity of the light-absorbing glass according to the composition of the light-absorbing glass;

[0079] 2) Detecting the temperature distribution on the surface of the light-absorbing glass specimen; determining the temperature mutation region and the volume size of the temperature mutation region according to the temperature distribution on the specimen surface;

[0080] 3) Continuously measuring the real-time temperature values of the light-absorbing glass specimen at different rod length positions; calculating the actual thermal conductivity of the light-absorbing glass according to the thermal radiation energy, the thickness and cross-sectional area of the light-absorbing glass rod specimen;

[0081] 4) Determining the type of internal defects according to the temperature distribution on the surface of the light-absorbing glass specimen; determining the material type of the internal defects according to the volume size of the temperature mutation region, the theoretical thermal conductivity of the light-absorbing glass, and the actual thermal conductivity of the light-absorbing glass.

[0082] In the above technical solution, the light-absorbing glass can be any light-absorbing glass. For example, it can be "a specific wavelength absorption type light-absorbing glass that has extremely high light absorption rate in a specific wavelength range, generally has extremely high absorption in the ultraviolet-visible light range, and has relatively high transmittance in the infrared band", as shown in Figure 1 Curve a. In the figure, the transmittance of the glass exceeds 60% in the near-infrared range of 0.8-1μm and the mid-infrared range of 2.5-4μm, and has relatively high absorption rate in other bands; it can also be "a full-spectrum absorption type light-absorbing glass that has good absorption rate in the ultraviolet-far infrared full spectrum range, and even if there is light transmission, its transmittance does not exceed 20%", as shown in Figure 1 Curve b.

[0083] For the heating of the light-absorbing glass specimen, non-contact irradiation heating can be carried out on it by infrared heating. The infrared heating method has strong inclusiveness for the light-absorbing glass specimen and has a wide range of applications. It can also be heated by the metal plate heating method. Since this heating method requires the metal plate to be in close contact with the glass to be heated during heating, its inclusiveness for the light-absorbing glass specimen is poor and it is only applicable to the heating of the light-absorbing glass with the same shape as the metal heating plate.

[0084] In the above technical solution, for the characteristic spectrum transmission type and the full spectrum absorption type light-absorbing glass, the present invention uses an active heating thermal imager based on an active type for non-destructive testing. By means of active heating, the internal defects of the glass are excited, so that a temperature difference distribution that can reflect its internal defects can be formed on the surface of the light-absorbing glass. Then, a highly sensitive cooled thermal imager is used for infrared thermal imaging to realize real-time monitoring of the temperature difference on the glass surface. The detection of the temperature difference on the glass surface is generally carried out while thermally exciting the glass or after a certain time delay of the thermal excitation.

[0085] The principle of measuring the internal defects of the glass by temperature detection through active thermal excitation in the technical solution of the present invention is as follows: When heat is injected into the light-absorbing glass, a part of the heat flow will inevitably diffuse into the glass interior and thus cause the temperature of the entire glass surface to change. For a defect-free glass, the heat flow is uniformly injected, and the heat can be uniformly diffused into the glass interior or from the surface, so the temperature field distribution on the glass surface also shows a uniform distribution. However, if there are defects in the interior of the glass specimen, a temperature difference will be formed between the defect area and the defect-free area of the glass specimen, and the temperature field distribution on the glass surface will also show a temperature change distribution.

[0086] The monitoring of the temperature of the light-absorbing glass can be carried out by reflection method monitoring or transmission method monitoring; reflection method monitoring means that the monitoring temperature surface is close to the heating radiation surface, while transmission method monitoring means that the monitoring temperature surface and the heating radiation surface are respectively located at two end faces of the light-absorbing glass. Generally, when there are thermal conductivity defects inside the light-absorbing glass, that is, the defect has a higher thermal conductivity coefficient, at this time, a local cold area with a lower temperature will appear on the glass surface during reflection method monitoring, and a local hot area will appear during transmission method monitoring; when there are heat insulation defects inside the light-absorbing glass, that is, the defect has a lower thermal conductivity coefficient, at this time, the heat flow transfer will be blocked at the defect, causing heat accumulation during reflection method monitoring, resulting in a local hot area with a higher temperature on the glass surface, and a local cold area will appear during transmission method monitoring. In this way, by monitoring the temperature of the glass surface after thermal excitation, it is possible to find out where on the glass there will be a temperature mutation, and there is an internal defect at the temperature mutation; further, it is possible to judge whether the internal defect at that place belongs to a thermal conductivity defect or a heat insulation defect according to whether the temperature mutation shows a prominent peak change or a concave valley change; further, the composition of the internal defect at that place can be judged through the thermal conductivity factor; further, the size of the internal defect can also be calculated through the fluctuation amplitude of the temperature mutation.

[0087] In the above technical solution, the temperature distribution on the surface of the light-absorbing glass specimen can be displayed as an image through a display, so that the temperature distribution on the surface of the light-absorbing glass specimen can be visually observed and understood; as shown in Figure 4a to Figure 4d shown.

[0088] When inspecting the internal defects of the light-absorbing glass, it is necessary to prepare it into a rod-shaped specimen. The light-absorbing glass specimen is round rod-shaped; the round rod-shaped specimen is required to have a flat surface, and its diameter deviation ≤ 0.1 mm; alternatively, the light-absorbing glass specimen is square rod-shaped; the four side surfaces of the square rod-shaped specimen are precision-ground surfaces and are perpendicular to each other, and the included angle between two adjacent side surfaces is 89.5° - 90.5°.

[0089] The specific operation of calculating the theoretical thermal conductivity of the light-absorbing glass according to the composition of the light-absorbing glass is as follows: Based on the fact that the internal thermal conductivity of the glass conforms to the addition principle, calculate the theoretical thermal conductivity λ1 of the light-absorbing glass according to the material composition of the light-absorbing glass, and the calculation formula is as follows:

[0090]

[0091] The above formula means that the material composition of the light-absorbing glass includes i kinds of raw materials, and then the sum of the products of the mass percentage content of each raw material multiplied by the density coefficient of this kind of raw material is obtained to get the theoretical thermal conductivity λ1 of the light-absorbing glass.

[0092] The specific operation steps for determining the volume size of the temperature mutation region based on the temperature distribution on the surface of the test piece are as follows: Radiative heating is carried out along the axis direction of the light absorption glass test piece, and the longest length of the internal defect along the rod length direction is measured as L z , and the cross-sectional area is S z ; Radiative heating is carried out along the cross-sectional direction of the light absorption glass test piece, and the longest length of the internal defect along the cross-sectional direction is measured as L j , and the cross-sectional area is S j ; According to the formula V=(S j ×L z +S z ×L j ) / 2 (Equation 2), the volume size of the temperature mutation region is calculated.

[0093] The specific process for calculating the actual thermal conductivity of the light absorption glass based on the thermal radiation energy, the thickness and cross-sectional area of the light absorption glass rod test piece is as follows: Thermal conductivity = (thermal radiation energy × thickness of the test piece) / (cross-sectional area of the test piece × temperature difference), where the thermal radiation energy applied to the glass (unit: calorie) is known, the thickness of the test piece (unit: centimeter), and the cross-sectional area (unit: square centimeter) are measurable, and the temperature difference (°C) is actually measured by a thermal imager.

[0094] The specific steps for determining the type of internal defect based on the temperature distribution on the surface of the light absorption glass test piece specifically include the following: Radiative heating is carried out along the axis direction of the light absorption glass test piece, and the detection result in this direction is obtained through a thermal imager; Radiative heating is carried out along the cross-sectional direction of the light absorption glass test piece, and the detection result in this direction is obtained through a thermal imager; Taking the position in the rod length direction of the light absorption glass test piece as the abscissa and the temperature at each position of the light absorption glass test piece as the ordinate, a temperature distribution curve is plotted; The temperature distribution curve may appear in a peak shape or a valley shape, and this is the temperature mutation region.

[0095] Generally, only solid and gaseous defects exist in the light-absorbing glass. The gaseous defects are internal defects such as bubbles, simply referred to as bubble defects; the solid defects are internal defects such as nodules, simply referred to as nodule defects. The thermal conductivity of the solid is greater than that of the gas. The thermal conductivity of the light-absorbing glass is more than 10 times that of the gas. When the glass contains bubbles, the heat transfer will be blocked, resulting in a lower temperature at the position with bubble defects than in other areas. In this case, the thermal conductivity factor in the temperature mutation region is less than the thermal conductivity of the light-absorbing glass, and the difference reaches two orders of magnitude, and the internal defect is a bubble defect; the bubble defect can be considered a kind of heat-insulating defect; if there are nodule defects of quartz type in the light-absorbing glass, since the main component of the quartz particles is silicon dioxide, and the light-absorbing glass is a mixed amorphous substance of various oxides, the thermal conductivity of the quartz particles should be 1.6 - 1.7 times that of ordinary glass, and the light-absorbing glass is a dark glass, and its thermal conductivity is lower than that of ordinary glass. Therefore, if there are unmelted quartz particles in the light-absorbing glass, this position will transfer the irradiated heat to the surface of the glass faster, resulting in a local temperature increase. In this case, the thermal conductivity factor in the temperature mutation region is greater than the thermal conductivity of the light-absorbing glass, and the difference reaches one order of magnitude, and the internal defect is a nodule defect, which can be regarded as a thermal conductivity defect; when the thermal conductivity of the internal defect in the light-absorbing glass is comparable to that of the glass matrix, the thermal conductivity factor in the temperature mutation region is basically comparable to the thermal conductivity of the light-absorbing glass. Then the internal defect at this place may be a nodule defect with the same main oxides as the light-absorbing glass matrix, or a nodule defect with a thermal conductivity similar to that of the light-absorbing glass; at this time, the change of its temperature distribution curve is not obvious, and it is difficult to determine the position and type of the defect. At this time, multiple measurements are needed for mutual verification, and the composition of the nodules is determined based on the thermal conductivity factor in the temperature mutation region combined with the infrared light intensity detection, that is, a comprehensive analysis is carried out by combining infrared light intensity detection and active thermal imaging detection.

[0096] The internal defect existing at the position where the peak shape is located on the temperature distribution curve is a nodule defect, and the internal defect existing at the position where the valley shape is located is a bubble defect.

[0097] During the detection, when radiatively heating along the axis direction of the light-absorbing glass specimen, the full width at half maximum of the peak shape or valley shape of the temperature distribution curve is equal to the longest length L of the internal defect along the rod length direction z ; when radiatively heating along the cross-sectional direction of the light-absorbing glass specimen, the full width at half maximum of the peak shape or valley shape of the temperature distribution curve is equal to the longest length L of the internal defect along the cross-sectional direction j; The full width at half maximum is calculated according to the following steps: obtain the highest value and the lowest value of the measured temperature of the peak shape or valley shape, and calculate the average value of the two; take this average value as the ordinate and draw a straight line parallel to the X-axis. The distance between the two intersections of this straight line and the temperature distribution curve is the full width at half maximum.

[0098] Determining the material type of the internal defect according to the volume size of the temperature mutation region, the theoretical thermal conductivity of the light-absorbing glass, and the actual thermal conductivity of the light-absorbing glass specifically includes the following steps: obtain the thermal conductivity and density data of the possible materials of the internal defect from the database; the database includes the corresponding data of various materials that may form internal defects; perform automatic calculation through computer software, and substitute the thermal conductivity and density data of the possible materials of the internal defect into the following formula to check whether the equation holds.

[0099]

[0100] In the above formula, λ0 represents the thermal conductivity of the internal defect, λ1 represents the theoretical thermal conductivity of the light-absorbing glass, λ2 represents the actual thermal conductivity of the light-absorbing glass, V represents the volume of the internal defect (unit: mm 3 ), and ρ0 represents the density of the internal defect (unit: g / mm 3 ).

[0101] If the equation does not hold, continue to substitute the thermal conductivity and density data of another possible material of the internal defect into the above formula for calculation to check whether the equation holds; the number of times of substituting the obtained material thermal conductivity and density data into the above formula for calculation is not limited, and it may exhaust various materials in the database until the thermal conductivity and density data of a certain material can make the above equation hold, then this material is determined as the material type of the internal defect.

[0102] The standard for the above equation to hold allows a certain error, and the allowable range of this error can be set according to the actual inspection requirements, generally it can be set within ±5%, or within ±2%, or within ±1%.

[0103] The present invention also proposes a detection system for internal defects of a light-absorbing glass. As shown in Attachment Figure 2 and Attachment Figure 3 , as a whole, it is an opaque vertical box structure, and the key detection components are all arranged in this opaque vertical box; the technical purpose of such a setting is to prevent the influence of infrared rays on the detection results.

[0104] In a specific embodiment of the present invention, the internal defect detection system of the light-absorbing glass includes a heating unit 1; the heating unit 1 is used to heat the light-absorbing glass specimen 2; the light-absorbing glass specimen may include internal defects 21; the detection system further includes a test platform (not marked in the figure), which can be a vertically placed bracket to facilitate the replacement operation of the active heat source; the test platform is used to place the heating unit 1 and the light-absorbing glass specimen 2; a bracket (not marked in the figure) and a three-dimensional precision mechanical transmission device (not marked in the figure) are also provided on the test platform; the three-dimensional precision mechanical transmission device is used to adjust the position of the light-absorbing glass specimen 2 in a three-dimensional space; the bracket is movably connected to the three-dimensional precision mechanical transmission device; the bracket is used to clamp the light-absorbing glass specimen 2; the bracket clamps the light-absorbing glass specimen 2 and its movement is controlled by the three-dimensional precision mechanical transmission device to achieve the position adjustment of the light-absorbing glass specimen 2 in a three-dimensional space; the detection system further includes a detection unit, which mainly includes a highly sensitive cooled thermal imager, or includes a highly sensitive cooled thermal imager and a spectrophotometer, for the purpose of monitoring the temperature field and measuring the intensity of the emitted infrared light; the detection unit is used to detect the temperature distribution on the surface of the light-absorbing glass specimen 2; the detection system further includes a frame (not marked in the figure), which can be an integral stainless steel material component; the frame is used to fix the detection unit; the detection system further includes a dark box 5, which aims to shield the influence of external and device itself infrared rays on the detection result; the dark box 5 includes a heat insulation layer to avoid or slow down the heat exchange between the inside of the dark box and the outside; the test platform and the detection unit are both arranged in the dark box 5; the detection system further includes a control unit 6, which mainly includes a dedicated computer and software to realize the automatic control of the whole detection process; the control unit 6 is electrically connected to the heating unit 1, the detection unit and the three-dimensional precision mechanical transmission device, controls the three-dimensional precision mechanical transmission device to move the light-absorbing glass specimen 2 to a specified position according to the instruction, the heating unit 1 heats the light-absorbing glass specimen 2, and controls the detection unit to monitor the temperature distribution on the surface of the light-absorbing glass specimen 2 in real time; the detection unit transmits the acquired data information to the control unit for result determination.

[0105] In a specific embodiment of the present invention, the positioning accuracy of the three-dimensional precision mechanical transmission device is ≤3.0 μm, and the repeat positioning accuracy is ≤2.0 μm; the technical purpose of such setting is to be able to accurately control the spatial position of the light-absorbing glass specimen 2 to ensure its relative position relationship with the heating unit 1, meet the requirements of high-precision detection, and thus enable the light-absorbing glass specimen 2 to be uniformly heated.

[0106] In a specific embodiment of the present invention, the three-dimensional precision mechanical transmission device includes a grating scale, a precision lead screw, and a precision guide rail; the grating scale adopts a British Renishaw closed grating scale with an accuracy of 0.5 μm; the precision lead screw adopts a Swiss ball-type C5 level; the precision guide rail adopts an SQ level. Using the three-dimensional precision mechanical transmission device for precision transmission is mainly to ensure the precise movement of the heat source and the light absorption glass to be measured, so as to realize the measurement of the temperature field and the infrared light transmission intensity of the light absorption glass at different positions.

[0107] In a specific embodiment of the present invention, there are two ways to inject heat into the light absorption glass in the present invention. One is the metal conductive hot plate type, and the other is the infrared heating panel type, that is, the heating unit 1 is a metal conductive hot plate or an infrared heating panel; different-shaped heat sources can be customized according to the shapes of different light absorption glass specimens.

[0108] In a specific embodiment of the present invention, a metal conductive hot plate is used for heating, and the detection unit is two thermal imagers 3; specifically, for the metal conductive hot plate method, two highly sensitive cooled thermal imagers are used to monitor the real-time temperature field of the light absorption glass surface and the heating plate respectively, and a real-time change curve of the glass surface temperature is obtained.

[0109] In a specific embodiment of the present invention, an infrared heating panel is used for heating, and the detection unit is two thermal imagers 3 and an infrared spectrophotometer 4; specifically, for the infrared heating panel type, two highly sensitive cooled thermal imagers are used to monitor the real-time temperature field of the light absorption glass surface and the heating panel respectively, and a real-time change curve of the glass surface temperature is obtained; at the same time, a portable infrared spectrophotometer is set on the infrared emission surface to monitor the change of the infrared light intensity on the glass emission surface, and comprehensive judgment and analysis are carried out by combining the real-time change curve of the glass surface temperature and the change of the infrared light intensity on the glass emission surface; the infrared spectrophotometer is an auxiliary detection method set for the infrared-transmitting light absorption glass, and its results are mutually verified with the detection results of the thermal imager to ensure the reliability of the detection. The infrared spectrophotometer is used to measure the light intensity of the continuous infrared band on the infrared output surface of the light absorption glass, and the type of defects inside the glass is analyzed through the change of the light intensity; the wavelength used by the infrared heating panel matches the wavelength of the infrared light transmitted by the light absorption glass.

[0110] In a specific embodiment of the present invention, a number of independent spaces that do not leak light from each other are provided in the dark box 5; each thermal imager 3 is placed in a different independent space; the technical purpose of such a setting is to ensure that there is no interference between each thermal imager when monitoring the temperature, so as to ensure the accuracy of the monitoring results.

[0111] In a specific embodiment of the present invention, the thermal imager adopts a high-sensitivity cooled thermal imager to reduce background noise and improve the accuracy and sensitivity of temperature monitoring. Specifically, the sensitivity of the thermal imager is higher than 0.025 °C, the temperature measurement accuracy is ±0.5 °C, and the temperature measurement range is 0 to 200 °C.

[0112] In a specific embodiment of the present invention, each of the thermal imagers is equipped with an independent display screen for composite display of thermal images / visual images. Each thermal imager detects and forms images independently without interference. In a dark room, they are respectively placed in mutually isolated spaces, and no light leakage is allowed between the two spaces.

[0113] In a specific embodiment of the present invention, the test wavelengths of the spectrophotometer are 290 nm to 2500 nm and 2500 nm to 10000 nm, the transmittance accuracy is ±0.2%, and the resolution is 5 nm.

[0114] The internal defect detection system for light absorption glass is a device dedicated to quickly testing the internal quality level of the light absorption glass required in optical fiber imaging elements. The specific detection process is as follows: Start the control software of the internal defect detection system for light absorption glass; Open the dark box, install the light absorption glass specimen on the bracket and place it at the zero position; Select different test heat sources, adjust the position of the light absorption glass to be measured so that the distances from each point on the heat source input surface of the glass to the heat source surface are the same; Close the dark box to make the test platform and the entire detection unit in a sealed dark operating environment and ensure no interference from external infrared rays; Turn on the control computer, turn on the heat source to heat the light absorption glass to be measured, and at the same time turn on the thermal imager and the spectrophotometer to monitor it in real time; When the monitoring results or the temperature distribution curve show sudden changes (sudden peak changes or sudden valley changes), the control system automatically analyzes the type of internal defects, the composition of internal defects, the location of internal defects, and the size of internal defects according to the preset program and gives the results; Restore the mechanical zero position, turn off the heat source, the spectrophotometer, the thermal imager, and the main power supply in sequence, take out the light absorption glass specimen and clean the dark room to complete the test work.

[0115] The present invention will be further described below in conjunction with specific embodiments, but it should not be construed as a limitation to the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention still fall within the protection scope of the present invention.

[0116] Unless otherwise specified, the materials, reagents, etc. involved below are all commercially available products well-known to those skilled in the art; Unless otherwise specified, the methods are all well-known methods in the art. Unless otherwise defined, the technical terms or scientific terms used should have the ordinary meaning understood by those of ordinary skill in the art to which the present invention belongs.

[0117] Example 1

[0118] The shape of the light absorption glass specimen to be measured is a round rod, and the diameter deviation is ≤ 0.1 mm.

[0119] Heating is carried out using a nickel-chromium alloy heating element; the shape of the nickel-chromium alloy heating element is customized according to the shape and size of the light absorption glass specimen to be measured; the temperature of the nickel-chromium alloy heating element is continuously controllable, and the non-uniformity of the surface temperature of the heating element is less than 0.5 °C.

[0120] The temperature measurement sensitivity of the refrigerated thermal imager is 0.025 °C, the temperature measurement accuracy is ±0.5 °C, the temperature measurement range is 0 to 200 °C, it is equipped with an independent display screen, and thermal image / visual image composite display is available.

[0121] The internal defect of the light absorption glass is a bubble of carbon dioxide.

[0122] Test: Detection is carried out according to the aforementioned operation procedure. First, radiant heating is carried out along the length direction of the light absorption glass rod. As shown in the appendix Figure 5 shown, the test results as shown in the appendix Figure 6a and appendix Figure 6b are obtained. The longest length of the defect along the rod length direction is L1, and the cross-sectional area is S1; according to the appendix Figure 6a and appendix Figure 6b the temperature distribution curve of the light absorption glass specimen to be measured is plotted, as shown in the appendix Figure 6c shown. Then, the test surface of the light absorption glass specimen is adjusted so that the light absorption glass specimen to be measured is radiantly heated along the cross-sectional direction of the light absorption glass. As shown in the appendix Figure 7 shown, the test results as shown in the appendix Figure 8a and appendix Figure 8b can be obtained. The longest length of the defect along the rod length direction is L2, and the cross-sectional area is S2; according to the appendix Figure 8a and appendix Figure 8b the temperature distribution curve of the light absorption glass specimen to be measured is plotted, as shown in the appendix Figure 8c shown.

[0123] It can be seen from the temperature distribution curve that there is a temperature mutation region in the shape of a trough, indicating that the internal defect in this embodiment is a bubble defect.

[0124] The theoretical thermal conductivity λ1 of the light absorbing glass is calculated according to the composition of the light absorbing glass; the actual thermal conductivity λ2 of the light absorbing glass is calculated according to the thermal radiation energy applied to the light absorbing glass specimen and the thickness, cross-sectional area and temperature difference detected by the thermal imager; the volume V of the internal defect is calculated according to the results of heating the light absorbing glass specimen along the axis direction of the specimen and in the cross-sectional direction of the specimen; the type of material of the internal defect is determined by automatic calculation and comparison according to formula 3) by computer software. It can be seen from the results of the above data processing that the internal defect in this embodiment is a bubble defect, and its component is carbon dioxide gas. The half-peak width obtained according to the temperature distribution curve is consistent with the actual measured value obtained by the thermal imager; in this embodiment, the size of the carbon dioxide bubble along the length direction of the glass rod is 60 to 70 mm, and the size along the cross-sectional direction is about 5 mm.

[0125] Example 2

[0126] The shape of the light absorption glass specimen to be measured is a square rod, the side of the square rod is a finely ground surface, the four side surfaces are perpendicular to each other, and the deviation is less than 1°C.

[0127] An infrared heating panel is used for heating. Its shape is customized according to the shape and size of the light-absorbing glass specimen to be measured. Its temperature is continuously controllable, and the non-uniformity of the surface temperature of the heating body is less than 0.5°C.

[0128] The temperature measurement sensitivity of the cooled thermal imager is 0.025°C, the temperature measurement accuracy is ±0.5°C, the temperature measurement range is 0-200°C, and it is equipped with an independent display screen and a thermal image / visual image composite display.

[0129] The test wavelengths of the spectrophotometer include 290nm~2500nm and 2500nm-10000nm, the transmittance accuracy is ±0.2%, and the resolution is 5nm.

[0130] The internal defects of light-absorbing glass are unmelted quartz grains.

[0131] Test: According to the above operating procedures, firstly, radiative heating is performed along the length direction of the light absorbing glass rod. Figure 9 As shown in the attached Figure 10a , Attachment Figure 10b The test results shown in the figure show that the longest length of the defect along the length of the rod is L3, and the cross-sectional area is S3. Figure 10a , Attachment Figure 10b The temperature distribution curve of the light absorbing glass specimen is drawn according to the test results, as shown in the attached figure. Figure 10c Then, adjust the test surface of the light absorbing glass specimen so that the light absorbing glass specimen to be tested is radiated and heated along the cross section of the light absorbing glass, as shown in the attached figure. Figure 11 As shown in the attached Figure 12a , Attachment Figure 12bThe test results are shown. The longest length of the defect along the rod length direction is L4, and the cross-sectional area is S4; according to the appendix Figure 12a and the appendix Figure 12b , draw the temperature distribution curve of the measured light absorption glass specimen, as shown in the appendix Figure 12c .

[0132] According to the temperature distribution curve, it can be seen that there is a temperature mutation region with a peak shape, indicating that the internal defect in this embodiment is a nodule defect.

[0133] Perform data processing in the same method as in Embodiment 1. In this embodiment, the internal defect is a nodule defect, and its component is quartz particles, generally unmolten quartz raw materials, quartz raw material aggregates. The full width at half maximum obtained from the temperature distribution curve is consistent with the measured value obtained by the thermal imager; in this embodiment, the size of the quartz particles along the glass rod length direction is 7-10 mm, and the size along the cross-sectional direction is about 3-4 mm.

[0134] Embodiment 3

[0135] The specimen, heating unit, and detection unit are the same as in Embodiment 2. The internal defect of the light absorption glass is an unmolten nodule rich in coloring ions.

[0136] Test: Perform detection according to the foregoing operation procedure. First, perform radiative heating along the length direction of the light absorption glass rod, as shown in Figure 13 , and obtain the test results as shown in the appendix Figure 14a and the appendix Figure 14b . The longest length of the defect along the rod length direction is L5, and the cross-sectional area is S5; according to the appendix Figure 14a and the appendix Figure 14b , draw the temperature distribution curve of the measured light absorption glass specimen, as shown in the appendix Figure 14c . Then, adjust the test surface of the light absorption glass specimen so that the measured light absorption glass specimen performs radiative heating along the cross-sectional direction of the light absorption glass, as shown in Figure 15 , and the test results as shown in the appendix Figure 16a and the appendix Figure 16b can be obtained. The longest length of the defect along the rod length direction is L6, and the cross-sectional area is S6; according to the appendix Figure 16a and the appendix Figure 16b , draw the temperature distribution curve of the measured light absorption glass specimen, as shown in the appendix Figure 16c .

[0137] According to the temperature distribution curve, it can be seen that the temperature change is not obvious, and the peak temperature is only 1-1.5 °C different from the matrix glass temperature, indicating that the thermal conductivity of the defect position is slightly higher than that of the nodule defect of the light absorption glass.

[0138] Data processing is performed by the method of Embodiment 1. In this embodiment, the internal defect is a knot defect, and its component is an unmelted manganese-rich particle. The full width at half maximum obtained from the temperature distribution curve is consistent with the measured value obtained by the thermal imager; in this embodiment, the size of the unmelted manganese-rich particle along the length direction of the glass rod is 6-7 mm, and the size along the cross-sectional direction is about 3-4 mm.

[0139] The technical features in the claims and / or the specification of the present invention can be combined, and the combination method is not limited to the combination obtained through the citation relationship in the claims. The technical solutions obtained by combining the technical features in the claims and / or the specification also fall within the protection scope of the present invention.

[0140] The above are only the preferred embodiments of the present invention, and do not impose any formal limitations on the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solutions of the present invention.

Claims

1. A method for detecting internal defects of a light-absorbing glass, characterized in that, It includes the following steps: 1) Heating a rod-shaped light absorption glass specimen; calculating the theoretical thermal conductivity of the light absorption glass according to the composition of the light absorption glass; 2) Detecting the temperature distribution on the surface of the light absorption glass specimen; determining the temperature mutation region and the volume size of the temperature mutation region according to the temperature distribution on the specimen surface; 3) Continuously measuring the real-time temperature values of the light absorption glass specimen at different rod length positions; calculating the actual thermal conductivity of the light absorption glass according to the thermal radiation energy, the thickness and cross-sectional area of the light absorption glass rod specimen; 4) Determining the type of internal defect according to the temperature distribution on the surface of the light absorption glass specimen; taking the position in the rod length direction of the light absorption glass specimen as the abscissa and the temperature at each position of the light absorption glass specimen as the ordinate to draw a temperature distribution curve; the internal defect existing at the position where the peak shape is located on the temperature distribution curve is a knot defect, and the internal defect existing at the position where the valley shape is located is a bubble defect; determining the material type of the internal defect according to the volume size of the temperature mutation region, the theoretical thermal conductivity of the light absorption glass and the actual thermal conductivity of the light absorption glass; The specific steps for determining the material type of the internal defect according to the volume size of the temperature mutation region, the theoretical thermal conductivity of the light absorption glass and the actual thermal conductivity of the light absorption glass are as follows: a. Obtaining the thermal conductivity and density data of the possible materials of the internal defect from the database; b. Substituting the thermal conductivity and density data of the possible materials of the internal defect into the following formula to check whether the following equation holds; Wherein, λ0 represents the thermal conductivity of internal defects, λ1 represents the theoretical thermal conductivity of the light absorption glass, λ2 represents the actual thermal conductivity of the light absorption glass, V represents the volume of internal defects, with the unit of mm 3 , ρ0 represents the density of internal defects, with the unit of g / mm 3 ; c. If the equation does not hold, replace it with another possible material of the internal defect and continue to execute steps a and b; if the equation holds, the possible material of this internal defect is determined as the material type of the internal defect.

2. The method for detecting internal defects of light-absorbing glass according to claim 1, wherein, The light absorption glass specimen is rod-shaped; the surface of the rod-shaped specimen is flat, and its diameter deviation ≤ 0.1 mm; or, the light absorption glass specimen is square rod-shaped; the four side surfaces of the square rod-shaped specimen are precision ground surfaces and are perpendicular to each other, and the included angle between two adjacent side surfaces is 89.5° - 90.5°.

3. The method for detecting internal defects of light-absorbing glass according to claim 1, characterized in that, The volume size of the temperature mutation region is determined according to the following steps: Radiative heating is carried out along the axis of the light-absorbing glass specimen, and the maximum length of the internal defect along the rod length is measured as L z , and the cross-sectional area is S z ; Radiative heating is carried out along the cross-sectional direction of the light-absorbing glass specimen, and the longest length of the internal defect along the cross-sectional direction is measured as L j , and the cross-sectional area is S j ; Calculate the volume size of the temperature mutation region according to the formula V = (S j × L z + S z × L j ) / 2.

4. The method for detecting internal defects of the light-absorbing glass according to claim 1, characterized in that, The specific steps for determining the type of internal defect according to the temperature distribution on the surface of the light absorption glass specimen are as follows: Performing radiant heating along the axis direction of the light absorption glass specimen, and obtaining the detection result in this direction through an infrared thermal imager; Performing radiant heating along the cross-sectional direction of the light absorption glass specimen, and obtaining the detection result in this direction through an infrared thermal imager.

5. The method for detecting internal defects of light absorption glass according to claim 4, wherein When performing radiant heating along the axis of the light-absorbing glass specimen, the full width at half maximum of the peak shape or valley shape of the temperature distribution curve is equal to the longest length L of the internal defect along the rod length z ; when performing radiant heating along the cross-section of the light-absorbing glass specimen, the full width at half maximum of the peak shape or valley shape of the temperature distribution curve is equal to the longest length L of the internal defect along the cross-section direction j ; the full width at half maximum is calculated according to the following steps: Taking the highest value and the lowest value of the measured temperature of the peak shape or the valley shape, calculating the average value of the two; taking this average value as the ordinate, making a straight line parallel to the X axis, and the distance between the two intersections of this straight line and the temperature distribution curve is the full width at half maximum.

6. An internal defect detection system for a light-absorbing glass, characterized in that, It includes: A heating unit for heating the light absorption glass specimen; A test platform for placing the heating unit and the light absorption glass specimen; A bracket and a three-dimensional precision mechanical transmission device are provided on the test platform; the bracket is used to clamp the light absorption glass specimen; the three-dimensional precision mechanical transmission device is used to adjust the position of the light absorption glass specimen in a three-dimensional space; A detection unit, which is used to detect the temperature distribution on the surface of the light absorption glass specimen; A frame, which is used to fix the detection unit; A dark box, which includes a heat insulation layer; the test platform and the detection unit are both arranged in the dark box; A control unit, electrically connected to the heating unit, the detection unit and the three-dimensional precision mechanical transmission device, controls the three-dimensional precision mechanical transmission device to move the light absorption glass specimen according to an instruction, the heating unit heats the light absorption glass specimen, and controls the detection unit to monitor the temperature distribution on the surface of the light absorption glass specimen in real time; the detection unit transmits the data information it obtains to the control unit for result determination; taking the position in the rod length direction of the light absorption glass specimen as the abscissa and the temperature at each position of the light absorption glass specimen as the ordinate to draw a temperature distribution curve; when there are sudden peak changes or depression valley changes in the monitoring result or the temperature distribution curve, the control system automatically analyzes the type of internal defect, the composition of internal defect, the position of internal defect and the size of internal defect according to a preset program and gives a result; the internal defect existing at the position where the peak shape is located on the temperature distribution curve is a knot defect, and the internal defect existing at the position where the valley shape is located is a bubble defect; The steps for determining the material type of the internal defect include: a. Obtain the thermal conductivity and density data of the possible materials of the internal defect from the database; b. Substitute the thermal conductivity and density data of the possible materials of the internal defect into the following formula to check whether the following equation holds; Wherein, λ0 represents the thermal conductivity of internal defects, λ1 represents the theoretical thermal conductivity of the light absorption glass, λ2 represents the actual thermal conductivity of the light absorption glass, V represents the volume of internal defects, in unit of mm 3 , ρ0 represents the density of internal defects, in unit of g / mm 3 ; c. If the equation does not hold, replace it with another possible material of the internal defect and continue to execute steps a and b; if the equation holds, the possible material of the internal defect is determined as the material type of the internal defect.

7. The internal defect detection system for light absorption glass according to claim 6, characterized in that, The positioning accuracy of the three-dimensional precision mechanical transmission device is ≤3.0 µm, and the repeat positioning accuracy is ≤2.0 µm.

8. The internal defect detection system for light-absorbing glass according to claim 6, characterized in that, The heating unit is a metal conductive hot plate or an infrared heating panel; when using the metal conductive hot plate for heating, the detection unit is two thermal imagers; when using the infrared heating panel for heating, the detection unit is two thermal imagers and an infrared spectrophotometer.

9. The internal defect detection system for light-absorbing glass according to claim 8, wherein, A number of independent spaces that do not leak light from each other are arranged in the dark box; each thermal imager is placed in a different independent space.

10. The internal defect detection system for light-absorbing glass according to claim 8, wherein The sensitivity of the thermal imager is higher than 0.025 °C, the temperature measurement accuracy is ±0.5 °C, and the temperature measurement range is 0 to 200 °C.

11. The internal defect detection system for light-absorbing glass according to claim 8, characterized in that, The test wavelength of the spectrophotometer is 290 nm to 2500 nm and 2500 nm to 10000 nm, the transmittance accuracy is ±0.2%, and the resolution is 5 nm.

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